Natural hazard — a condition certain parts of the lithosphere, hydrosphere, atmosphere or space, representing a threat to people, economic facilities, technosphere and biotechnosphere.
The natural levels of danger depends on the frequency and strength of natural hazards spatial characteristics (areas of development or areas of negative factors of adverse natural phenomena, the spatial distribution of foci of occurrence of extreme natural phenomena).
Anthropogenic hazard — a condition in which negative factors, emerging mainly waste of human activities (industry, agriculture, energy, transport, everyday life, animals) that pose a threat to human health and the environment.
Technological hazard — a condition in which negative factors are emerging in the areas of technological processes, technical systems and objects that pose a threat to the health of industrial personnel and the population.
The degree of technological risk in the first place depends on the types and number of potentially dangerous objects accumulated on their potential risk, reliability and resilience of technological systems, the distance from places of human habitation.
Danger areas — state of the territory characterized by the presence of sources of natural and man-made hazards. These dangers pose a threat to the livelihoods of people living in the area. The threat occurs when economic development areas where possible adverse natural phenomena, as well as possible the damaging factors of extreme natural phenomena, and factors of accidents, catastrophes and natural disasters.
The source of danger is limited to a certain region of space the processes that can lead to negative impacts on people, the objects of the technosphere and the natural environment. Such area there may be areas of possible occurrence of natural hazards, the burial place of toxic wastes, industrial facilities, industrial areas and residential areas with the infrastructure as a whole.
Accompanying the vital functions of human life can be classified by: origin, distribution in space, feasibility, uncertainty of location, duration and frequency of activity.
According to the sources, which can be natural environment, the technosphere and the society, allocate natural (natural disasters) anthropogenic (fires, explosions, accidents, disasters), biological and social (epidemics, epizootics, epiphytotics) of danger.
The degree distribution in the space of risk are divided into focus (from individual compact objects) and distributed by the coordinates (from Railways, pipelines) or surface area (areas, zones), which include areas of environmental pollution and possible emergency situations: earthquake zones, landfills, positioning areas of missile divisions, naval bases, airports, and areas of hostilities or active terrorist activities.
On the feasibility of distinguish risk from harmful objects (harmful or adverse for the life of the areas) and potentially hazardous objects (regions). For example, objects containing sources of ionizing radiation are harmful in the course of normal operation, and the far North — adverse. The areas of high hazard are previously contaminated areas associated with the development of the technosphere, such as the development, testing, operation and liquidation of nuclear and radiation-dangerous objects; with earlier man-made disasters.
Potentially dangerous object — the object on which use, produce, process, store or transporterowych radioactive, fire and explosion hazard, hazardous chemical and biological substances creating real threat of occurrence of emergency situations source. These include nuclear, chemical and biological production, explosive objects, objects of weapons and military equipment, waterworks waterfront and regulating water flow, etc., which has considerable destructive energy potential or contain substantial amounts of substances which due to their physical, chemical, biological and toxico-logical properties predetermine a danger to life and health of people, agricultural animals and plants (potentially hazardous substances).
Potential danger includes the natural environment (realized in the form of extreme events — natural disasters, which in urbanized areas can lead to loss of life, destruction or destruction of objects and components of the environment) and society itself (manifested in the form of epidemics of serious crimes, terrorist acts, extreme forms of social protest). For example, social tensions, as a source of danger, manifested in such forms of social protest, like strikes, demonstrations, civil disobedience, blocking highways, rebellion, revolution. Unresolved inter-ethnic relations, ethnic conflicts are a source of danger for the territorial integrity of the country, which is evident in the growth of separatism, terrorism. These dangers cause potentially dangerous areas — territories of possible emergency situations.
Danger share:
on the uncertainty of the location — known (stationary hazard, volcano, zones of flooding and floods, etc.) and unknown (random) coordinates (e.g., location of possible pipe break, transport accident, the epicenter of the earthquake, etc.);
on the duration — short-term (implemented in the form of dangerous events) and long (harmful objects during normal operation, environmental pollution) current; for the regularity of actions implemented on time and on the scale randomly (in the form of random events), and deterministic (continuous factors of environmental pollution; hazards accompany normal use of technosphere objects, such as uranium mines, nuclear reactors, chemical plants).
People, creating processes, provides for the presence of dangers and the ability to manage their impact on the human body were commensurate with its tolerance (tolerance to risks). Such dangers are called regular. Natural system — biosphere — also has a "regular" risk, the impact of which on plants, animals, microorganisms, i.e., the living components of the ecosystem, do not cause noticeable changes. The quantitative values of the regular dangers of anthropogenic and natural origin are in the region of maximum permissible exposure levels for industrial and domestic human activities, and for organisms of nature — within the factors they occupy ecological niches.
In the process of maintenance of technical systems and technological processes, the formation of conditions of transition of the regular hazards in emergency, i.e., unintended technology (the unreliability of technical systems, human error, influence of natural factors, etc.). In the natural environment due to a change in the nature of meteorological, hydrological, geological and other processes possible "emergency" nature of the situation, which considerably strengthens the negative effect of natural forces. Such contingency in human activity and the forces of nature, as a rule, lead to emergency situations.
An emergency is a situation in the certain territory, developed as a result of an accident, hazardous natural phenomena, catastrophe, natural or other disaster which can entail or entailed human victims, the damage to human health or the environment, considerable material losses and violation of conditions of activity of people.
Thus, emergency identifitseerida on emerging (projected) damage (harm, damage). This damage is manifested through the effects of natural or technological hazards, is the source of the emergency. Under the impact refers to the result of exposure to damaging and other factors accompanying the disaster on human, economic facilities, social sphere, environment, and changes in environment that occurred as a result. In other words — the presence of a particular type of damage is a prerequisite in which the current situation can be characterized as an emergency.
In the study of problems of safety in emergency situations introduces the concept of danger in an emergency.
The danger in an emergency — a condition in which was created or high probability of affecting factors and impacts source of the emergency on the population, objects of economy, infrastructure and the environment in emergency zone, i.e. in the territory where an emergency situation.
The degree of hazard depends on the probability of its realization, energy, toxic and other power affecting factors, but also from the vulnerability and security of the hazardous object from external dangers.
Natural and man-made hazards are usually in the form of challenges and threats.
The challenge is the form of danger, represents the totality of the circumstances, generating a hypothetical danger, which in the future can turn into immediate danger. Examples of challenges in the field of natural and technogenic safety are danger of falling to the Ground large bodies, the growing global climate change, the prospects of creating a new hazardous industries, weapons etc. Early detection and awareness of the challenge is very important because it allows you to advance to take measures to prevent the transfer of risk as a form of threat.
The threat is a form of risk in natural and technogenic spheres, which is a direct risk of natural and man-made disasters, as well as the circumstances that stimulate these phenomena. In them can be natural and man-made patterns that contribute to danger: the techno-economic backwardness, structural and functional deficiencies of the system security, the intention to cause damage, incorrect assessment of the degree of danger of neratzia-tional nature.
In terms of forms of risk, note that the boundaries between them are to some extent conditional. So there are some difficulties of a clear separation challenges and threats together. The most used and common in the practice of form of danger is a threat.
Dangers pose a threat only when can cause harm to specific projects. Hazard or several hazards pose a threat to the object only if their threat factors can affect the right. The threat of damage depends on the mutual position of the source of the risk and object exposure to its hazards in space and in time (for stationary objects only in space). For example, for people the threat occurs when they work in high risk or in the zone of contamination; for the moving objects at their location in a dangerous area. The degree of threat to the life of the population in the study area depends on the degree of hazard, and also on geographical and temporal factors. If the object is moved beyond this area, the threat to him, although the danger areas for the remaining items will remain. The threat to life varies over time: it can arise, grow, decline and disappear.
The geographical factor is associated with local manifestation of the dangers of its uncertain location in the case of implementation, the weakening of the levels of the damaging factors with distance from the source of danger. The closer the objects and people are located in relation to the source of danger (known or assumed), the greater the risk.
When you move an object close to a potentially dangerous object or area of possible emergency situations, the time factor is considered as the probability that the object at the time of the hazardous events will be in the area of the damaging factors of source emergency.
If the time of occurrence of hazardous events can be predicted, the threat object depends on the magnitude of the error of the 1st kind — the probability that a harmful event in the considered time interval has occurred, although it was not predicted (and therefore protective measures were not taken).
The threat to people from natural and manmade hazards considered for two cases:
a) people vulnerable to primary damaging factors of extreme natural phenomena or accidents;
b) people are immune to the primary damaging factors, but are vulnerable to secondary damaging factors, formed during the destruction of buildings and constructions (for example, in case of an earthquake).
In the first case, the assessment of threat for people is similar to the risk assessment for objects of the technosphere.
In the second case, the threat to humans occurs when there is a threat to technosphere objects, provided their presence in the moment of extreme natural phenomena or accidents in buildings and structures. The degree of risk in this case depends on the fraction of time spent by an arbitrary person from certain groups are vulnerable to damaging factors extreme weather events buildings and facilities. The closer people are to the source of the danger and greater the length of time spent in the zone of actions or possible actions of the threat factors, the greater the risk. Her degree is characterized by certain parameters:
for potentially dangerous objects and areas of possible emergency situations the conditional probability of exposure to damaging factors in case of realization of threat events in a given place at a given time (primary affecting factors; the secondary striking factors, such as the case in buildings in case of earthquakes, explosions); for harmful objects and areas where the risk is characterized by deterministic exposure levels (concentrations of harmful substances, dose of radiation, etc.), the dose received by them during the stay in hazardous area. In the future, the risk of harm to health is determined by the dependence "dose — effect". The threat to people changes over time. With the increasing danger threat also increased. As a result of implementation of measures to reduce risk, protect facilities equipment and people, the threat is reduced.